Drive for a movable furniture part

ABSTRACT

Drive for a movable furniture part, comprising a motor to power the movable furniture part and a control or regulation unit to control or regulate the motor, wherein the control or regulation unit is designed such that it has a threshold value which, if surpassed, causes the actuation of the movable furniture part by the motor, wherein a measurement device is provided to capture the position of the movable furniture part and that the control or regulation unit is designed in such a way that the threshold value varies for at least two different positions of the movable furniture part.

The present invention relates to a drive for a movable furniture part, comprising a motor to drive the movable furniture part and a control or regulation unit to control or regulate the motor, wherein the control or regulation unit is designed in such a way that it has a threshold value and if this value is exceeded, this actuates the driving of the movable furniture part by the motor.

A drive of this type is disclosed for example from EP 1 374 732 A1. Obviously, every control or regulation unit has a certain threshold value which must be exceeded so that the control or regulation unit becomes active. This threshold value, however, is completely independent of external values. Contrary to this, the aforementioned patent document describes, in paragraph 35, a control device which has different threshold values for the triggering of the motor as a function of the direction of movement of the movable furniture part. In this case the threshold value is a distance to be covered by the movable furniture part.

In the drive described in EP 1 374 732, shaking movements of the furniture can lead to incorrect triggering of the motor. For example, especially when the movable furniture part is in a half-open position, it can happen that the shaking movements which arise when items are being placed in the movable furniture part are so great that the movable furniture part is moved by more than 1 mm away from the furniture body. This leads to a per se unintentional triggering of the motor, as the result of which the movable furniture part is accelerated in the direction of the fully-open end position. Behaviour of this type is regarded by most users as undesirable.

The problem of the invention is therefore to refine a generic drive in such a way that the risk of unintentional triggering is reduced.

This problem is solved by a drive with the features of claim 1.

The threshold value can, for example, relate to the amount of a motion quantity of the movable furniture part, such as speed or acceleration. Alternatively, the threshold value can also relate to the amount of a force exerted by a user on the movable furniture part. In each of the cases mentioned, obviously a suitable measurement device must be provided to capture the respective values.

It would of course also be possible to make use of the measurement device which must be provided anyway to capture of the position of the movable furniture part, and to use a distance to be covered by the movable furniture part as threshold value for the control or regulation unit.

The concept according to the invention makes it possible to design the control or regulation unit in such a way that when the drive is in the installed condition on a furniture body, the threshold value for the closed end position of the movable furniture part in or on the furniture body differs from the threshold value for the fully-open end position of the movable furniture part.

For example, provision can be made that the threshold value in or on the furniture body is lower than the threshold value for the fully-open end position of the movable furniture part. This measure takes into account the fact that in its closed end position, the movable furniture part is scarcely exposed to any unintentional force effects. By selecting a lower threshold value in this end position, it is therefore possible to react earlier to the desire for actuation by a user. In the fully-open end position of the movable furniture part, however, there may arise unintentional influences of force due to the putting in or taking out of objects from the movable furniture part. A higher threshold value is therefore selected.

Provision may also be made that in the installed position of the drive on a furniture body, the threshold value for each position between the closed end position and the fully-open end position of the movable furniture part is higher than the higher of the two threshold values for the closed end position and the fully-open end position of the movable furniture part. Especially in the case of a partly-opened movable furniture part, unintentional shaking movements often occur which is why the control or regulation unit should react with the least sensitivity in this area.

Obviously it is possible, in addition to the aforementioned measures, as already described in EP 1 374 732 A1, to select the threshold value as a function of the direction of movement of the movable furniture part.

The movable furniture part can in this case for example be a drawer.

Protection is further requested for a piece of furniture with a furniture body and a movable furniture part which can be moved in or on the furniture body and wherein a drive according to one of the aforementioned embodiments is arranged.

Further advantages and details of the invention are disclosed with the aid of the figures and of the following description of the figures, which show:

FIG. 1 a schematic view of a drive according to the invention,

FIG. 2 an illustration of the threshold value as a function of the position of the movable furniture part,

FIG. 3 a schematic view of a further embodiment of a drive according to the invention,

FIG. 4 a, 4 b a perspective view and a top view of the embodiment shown schematically in FIG. 3 and

FIG. 5 a top view of a piece of furniture with a drive as shown in FIGS. 3 and 4 a, 4 b.

FIG. 1 shows a schematic view of a piece of furniture 3 with a furniture body 4 in which a movable furniture part 2 in the form of a drawer runs on bearings. A drive 1 is provided to move the movable furniture part, said drive comprising a motor 5, a cable pull 8 and a deflection pulley 10. The cable pull 8 is coupled with the movable furniture part 2 by means of a carrier 9. In the example shown in FIG. 1, the motor 5 itself includes the control or regulation unit and a measurement device to capture the position of the movable furniture part. The measurement device used here is an optical or inductive encoder, which is coupled with the roller of the cable pull 8 disposed on the motor side, not visible in FIG. 1. The encoder can measure the rotation angle and the speed of rotation of the cable pulley and thus the position, speed and acceleration of the movable furniture part. In this sense, the measurement device for capturing the position of the movable furniture part 2 also serves as a measurement device to capture the speed and/or acceleration of the movable furniture part.

In FIG. 2, the threshold value S is shown via the position x of the movable furniture part 2 shown in FIG. 1. In the position x₀ the movable furniture part 2 is in its closed end position in the furniture body 4. In the position x₃ the movable furniture part 2 is in its fully-open end position. In the positions x₁ and x₂ the movable furniture part 2 is in an intermediate position between the closed end position and the fully-open end position. It can be seen in FIG. 2 that the threshold value S between the positions x₀ and x₁ has a first value S₁. This area is in front of the closed end position of the movable furniture part 2 in the furniture body 4. In the area between the positions x₂ and x₃ the movable furniture part 2 has a second threshold value S₂. This area is in front of the fully-open end position of the movable furniture part 2. In the area between positions x₁ and x₂ the threshold value finally has a third value S₃. This area corresponds to a partial outward movement of the movable furniture part 2 from its closed end position.

Since the movable furniture part 2, in its closed end position in the furniture body 4, is least sensitive to unintentional force effects, the lowest value S₁ is selected for this area. The value S₂ for the area in front of the fully-open end position of the movable furniture part 2 is already selected to be somewhat higher since the movable furniture part 2 is exposed to stronger disruptive influences in this area. The threshold value S₃ is selected to be the highest since an only partly-opened movable furniture part 2 is most sensitive to an unintentional triggering.

In FIG. 3, a further embodiment of an inventive drive 1 is shown. The drive 1 comprises a motor 5 in the form of an electromotor, a clutch 11 for an axial tolerance compensation, an engaging and disengaging clutch 12, an output 13 and a measurement device 7 to capture the position and motion quantities of the movable furniture part 2. Furthermore, a control or regulation unit 6 is provided, which communicates via cables 16 with the motor 5, the engaging and disengaging clutch 12 and the measurement device 7. The measurement device 7 can, as in the aforementioned embodiment, include an encoder which measures the rotation angle and the rpm of the output 13. The output 13 drives the movable furniture part 2 via a cable pull 14 which is steered via a deflection pulley 15. The engaging and disengaging clutch 12 can be disengaged and engaged by the control or regulation unit 6, as the result of which the exertion of force by the motor 5 on the output 13 can be interrupted or restored respectively.

In FIGS. 4 a and 4 b, the drive 1 which is shown only schematically in FIG. 3 is shown in more detail. Especially recognisable here are the encoder 16 coupled to the output 13 and the clutch 11 for the axial tolerance compensation which has a compressible area for this purpose. This means the drive 1 can be adapted to the dimensions of the furniture body for installation in a furniture body.

In FIG. 5, the drive 1 is shown in its installed position on a furniture body 4. It is now possible to see the coupling of the cable pull 14 via a carrier 18 on the rear wall 17 of a movable furniture part 2, not otherwise shown in more detail.

For the embodiment shown in FIGS. 3 to 5, a progression of the threshold value S as a function of the position x of the movable furniture part 2 according to FIG. 2 is also provided. 

1. Drive for a movable furniture part, comprising a motor to power the movable furniture part and a control or regulation unit to control or regulate the motor, wherein the control or regulation unit is designed such that it has a threshold value which, if surpassed, causes the actuation of the movable furniture part by the motor, wherein a measurement device is provided to capture the position of the movable furniture part and that the control or regulation unit is designed in such a way that the threshold value varies for at least two different positions of the movable furniture part.
 2. Drive according to claim 1, wherein a measurement device to capture at least one motion quantity of the movable furniture part is provided and that the threshold value relates to the amount of the at least one motion quantity.
 3. Drive according to claim 2, wherein the at least one motion quantity is the speed or the acceleration of the movable furniture part.
 4. Drive according to claim 1, wherein a measurement device is provided to capture a force exerted by a user on the movable furniture part and that the threshold value relates to the amount of force.
 5. Drive according to claim 1, wherein the control or regulation unit is designed in such a way that when the drive is in the installed condition on a furniture body the threshold value for the closed final position of the movable furniture part in or on the furniture body differs from the threshold value for the fully-open end position of the movable furniture part.
 6. Drive according to claim 5, wherein the threshold value in or on the furniture body is less than the threshold value for the fully-open end position of the movable furniture part.
 7. Drive according to claim 5, wherein when the drive is in the installed condition on a furniture body the threshold value for each position between the closed final position and the fully-open end position of the movable furniture part is higher than the higher of the two threshold values for the closed end position and the fully-open end position of the movable furniture part.
 8. Drive according to claim 1, wherein the motor is in the form of an electromotor.
 9. Furniture with a furniture body and a furniture part movable in or on the furniture body, wherein a drive according to claim 1 is arranged. 